(a) Field of the Invention
This invention relates to tripeptide derivatives which are characterized by having a N-(thiopropanoyl)-proline residue. The derivatives are antihypertensive agents. The invention also relates to a process for preparing these derivatives, pharmaceutical compositions thereof and to a method for using these derivatives.
(b) Prior Art
The angiotensin-converting enzyme is part of the renin-angiotensin system; for instance, see E. G. Erdos, Federation Proc., 36, 1760 (1977). The enzyme converts angiotensin I to angiotensin II, the most potent naturally occurring pressor substance known. Recently, a number of inhibitors of this enzyme have been found, e.g. see D. W. Cushman et al., Biochemistry, 16, 5484 (1977). One of the more interesting of these inhibitors, 1-(3-mercapto-2-D-methyl-1-oxopropyl)-L-proline (captopril) has been shown to be a clinically effective antihypertensive agent.
The present invention provides compounds which are extremely effective inhibitors of this enzyme.